Merge branch 'master' of git://1984.lsi.us.es/nf-next
[linux-3.10.git] / net / ipv6 / tcpv6_offload.c
1 /*
2  *      IPV6 GSO/GRO offload support
3  *      Linux INET6 implementation
4  *
5  *      This program is free software; you can redistribute it and/or
6  *      modify it under the terms of the GNU General Public License
7  *      as published by the Free Software Foundation; either version
8  *      2 of the License, or (at your option) any later version.
9  *
10  *      TCPv6 GSO/GRO support
11  */
12 #include <linux/skbuff.h>
13 #include <net/protocol.h>
14 #include <net/tcp.h>
15 #include <net/ip6_checksum.h>
16 #include "ip6_offload.h"
17
18 static int tcp_v6_gso_send_check(struct sk_buff *skb)
19 {
20         const struct ipv6hdr *ipv6h;
21         struct tcphdr *th;
22
23         if (!pskb_may_pull(skb, sizeof(*th)))
24                 return -EINVAL;
25
26         ipv6h = ipv6_hdr(skb);
27         th = tcp_hdr(skb);
28
29         th->check = 0;
30         skb->ip_summed = CHECKSUM_PARTIAL;
31         __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
32         return 0;
33 }
34
35 static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
36                                          struct sk_buff *skb)
37 {
38         const struct ipv6hdr *iph = skb_gro_network_header(skb);
39         __wsum wsum;
40         __sum16 sum;
41
42         switch (skb->ip_summed) {
43         case CHECKSUM_COMPLETE:
44                 if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
45                                   skb->csum)) {
46                         skb->ip_summed = CHECKSUM_UNNECESSARY;
47                         break;
48                 }
49 flush:
50                 NAPI_GRO_CB(skb)->flush = 1;
51                 return NULL;
52
53         case CHECKSUM_NONE:
54                 wsum = ~csum_unfold(csum_ipv6_magic(&iph->saddr, &iph->daddr,
55                                                     skb_gro_len(skb),
56                                                     IPPROTO_TCP, 0));
57                 sum = csum_fold(skb_checksum(skb,
58                                              skb_gro_offset(skb),
59                                              skb_gro_len(skb),
60                                              wsum));
61                 if (sum)
62                         goto flush;
63
64                 skb->ip_summed = CHECKSUM_UNNECESSARY;
65                 break;
66         }
67
68         return tcp_gro_receive(head, skb);
69 }
70
71 static int tcp6_gro_complete(struct sk_buff *skb)
72 {
73         const struct ipv6hdr *iph = ipv6_hdr(skb);
74         struct tcphdr *th = tcp_hdr(skb);
75
76         th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
77                                   &iph->saddr, &iph->daddr, 0);
78         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
79
80         return tcp_gro_complete(skb);
81 }
82
83 static const struct net_offload tcpv6_offload = {
84         .callbacks = {
85                 .gso_send_check =       tcp_v6_gso_send_check,
86                 .gso_segment    =       tcp_tso_segment,
87                 .gro_receive    =       tcp6_gro_receive,
88                 .gro_complete   =       tcp6_gro_complete,
89         },
90 };
91
92 int __init tcpv6_offload_init(void)
93 {
94         return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
95 }